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Jon,
The pictorial that shows "3 amp slo-blo" is probably the pictorial that I enhanced with color. All the original Dynaco pictorials had no color. In the Stickys above under "Dynaco Tube Pictorials" is a large version of the enhanced Mark III pictorial. Below is a smaller version of the same pictorial.
Bob 
I was looking at my schematics of the Mk III and saw something I didn't notice before; one schematic shows 3A slow blow fuse and the other one shows a regular 3A fuse.
What's up with that?
Jonathan
I discovered something interesting today. I have two schematics of the MK III; one has a 3 amp slow blow fuse and the other schematic shows a regular 3 amp fuse.
I'm using regular 3 amp fuses. Maybe that's why my fuse blew. (it's been OK since I replaced it)
Jonathan
Bob Latino wrote:Hup,
Some people, when they do this, trace the wire from lug # 1 and find that it goes to ground? and say "This can't be right ? Positive to GROUND" but it is. The bias system runs a negative DC voltage to control the flow of current through the output tubes and everything is in REVERSE - positive to chassis ground.
Bob
Hup,
Most people start on the bias system by replacing the stock selenium rectifier with a diode. Because a diode has more forward voltage flow than a selenium rectifier, the replacement usually throws off range at which the bias system operates.
The usual procedure is to add resistors in parallel to the two bias resistors on the 7 lug terminal strip. This will drop the total resistance and allow an expansion to the range in which the bias system operates. Try paralleling another 10K resistor with the one that is already there on lugs 1 and 2. This will give you 5 K. Try paralleling a 15K to 27K resistor to the 10 K resistor on lugs 3 and 4 to give an effective resistance of about 6K to 7K or so. A 1/2 watt resistor should be OK here. While your at it you should replace the two 50 Uf capacitors between lugs 1 and 3 and 1 and 4 with new 100 Mfd at 100 volts or higher. Make sure that you orient the capacitors properly with the positive (+) side of both capacitors connected to lug #1. Some people, when they do this, trace the wire from lug # 1 and find that it goes to ground? and say "This can't be right ? Positive to GROUND" but it is. The bias system runs a negative DC voltage to control the flow of current through the output tubes and everything is in REVERSE - positive to chassis ground.
Bob